Tzav

In the synagogue the Torah is read aloud in a fixed annual cycle of fifty-four weekly portions (parashiyot), one each Shabbat morning, with certain adjacent portions doubled in ordinary years so the sequence fits the calendar. Each portion is named for a distinctive word near its opening and is paired with a haftarah, a reading from the Prophets. The cycle closes and restarts on Simchat Torah. Tzav ('Command', Leviticus 6:1-8:36) continues the sacrificial law from the priests' perspective, the tending of the altar fire, the portions of the priests, and describes the seven-day consecration of Aaron and his sons to the priesthood.

Tzav's instruction that the fire on the altar 'shall be kept burning, it shall not go out' (Leviticus 6:13) is read by rabbinic commentary as establishing a continuous, uninterrupted flame maintained by the priesthood, later tradition holding that this perpetual fire persisted throughout the First and Second Temple periods and became a model, in later synagogue architecture, for the ner tamid, the eternal light kept burning before the ark in synagogues to this day. The consecration of Aaron and his sons across a full seven days, during which they were confined to the sanctuary entrance and repeated the ordination rites daily (Leviticus 8:33-35), is read by commentators as establishing the pattern, echoed in later Jewish law's seven-day periods for other transitions including mourning, of a full week as the span necessary for a significant change in status to be fully effected.

The instruction that the altar fire never be extinguished (Leviticus 6:13) finds broad parallels in other ancient traditions of maintained sacred fire, most famously the Vestal virgins' perpetual flame in ancient Rome and the ever-burning fires of Zoroastrian fire temples, comparisons historians of religion draw to illustrate a recurring human instinct to mark the sacred through unbroken continuity rather than to claim any direct historical connection between the traditions. Source critics attribute Tzav, like the surrounding sacrificial legislation, to the Priestly source, and note that Tzav deliberately restates much of the preceding portion Vayikra's material from a different vantage: where Vayikra instructs the ordinary Israelite bringing an offering, Tzav instructs the priest performing it, a paired structure read as a deliberate literary strategy rather than redundancy.

The seven-day confinement of Aaron and his sons at the sanctuary entrance during their ordination (Leviticus 8:33-35) is echoed in later rabbinic practice requiring the high priest to be secluded for seven days before Yom Kippur, a precedent the Mishnah's tractate Yoma cites explicitly, showing this portion's ordination pattern still governing Second Temple practice many centuries after Sinai.